Hypoxia in extravillous trophoblasts links maternal obesity and offspring neurobehavior.

While maternal obesity (MO) is associated with neurobehavioral impairment (NBI) in offspring, the underlying mechanisms remain unknown. The placenta is thought to play a role in fetal programming. To elucidate the association between MO and offspring NBI, we performed single-nucleus RNA-seq on maternal- and fetal-facing sides of human term placentas from MO and lean groups. MO placentas showed the upregulation of hypoxia response genes in multiple cell types, and maternal-facing hypoxia gene expression correlated with offspring NBI in an independent birth cohort, Gen3G. Extravillous trophoblasts (EVTs) showed the highest expression of NBI-correlated genes, and EVT NBI-gene expression correlated with hypoxia signatures in two cohorts. Exposing cultured EVTs to hypoxia increased NBI gene expression, and 44% of the association between maternal BMI and NBI-gene expression in EVTs was mediated by hypoxia. Our findings suggest that hypoxia in EVTs is a key process in the neurodevelopmental programming of fetal exposure to MO.